Blue dye and process of making same.



UNrTnn STATES PATENT OFFICE.

CHARLES DE LA HARPE, OF BASLE, SWITZERLAND, ASSIGNOR TO THE FIRM OF DYE WORKS, FORMERLY L. DURAND, HUGUENIN & 00., OF

BASLE, SWITZERLAND.

BLUE DYE AND PROCESS OF MAKING SAME.

SPECIFICATION forming part of Letters Patent No. 707,832, dated August 26, 1902.

Application filed February 27, 1902. Serial No. 95,993. (Specimens) T0 aZZ whom it may concern.-

Be it known that I, CHARLES DE LA HARPE, chemist, a citizen of the Swiss Republic, and a resident of Basle, Switzerland, have invented new and useful Improvements in the Manufacture of Blue Dyestuffs, of which the following is a full, clear, and exact specification.

In treating the sulfonic gallocyanins obtained by the reaction of a nitrosoalkylbenzylanilinsulfonic acid upon gallic acid or its derivatives-such as gallamic acid, ethers of gallic acid, gallanilide, &O.-by sulfurous acid in a free state or in form of a sulfite or bisulfite derivatives are obtained which are analogous to those of the Letters Patents No. 613,578 of November 1, 1898, No. 638,576 of December 5, 1899, and No. 662,224 of November 20, 1900, but which dye in different shades.

Example Fifty kilos of the gallocyanin obtained by the reaction of the nitrosoethylbenzylanilinsulfonic acid upon gallamic acid are intimately mixed with a solution of thirtyfour kilos of crystallized neutral sodium sulfite in four hundred liters of water. The mass is then heated in a closed vessel on a water-bath during some hours while being well stirred. Thirty kilos of hydrochloric acid of 20 Baum are then added in order to drive out the uncombined sulfurous acid, whereupon precipitation is effected by common salt. The grayish mass thus obtained is then isolated by filtration and pressed. This coloring-matter is soluble in sodium acetate with a pale-blue color. It dyes chromiummordanted fibers in blue shades. Its soluing agent.

resulting from the reaction of the nitrosoethylbenzylanilinsulfonic acid upon gallamic acid may be replaced by any other sulfonic gallocyanin obtained by the reaction of a nitrosoalkylbenzylanilinsulfonic acid upon gallio acid or one of its derivatiessuch as gallamic acid, ethers of gallic acid, gallanilide, 85c. Likewise the neutral sodium sulfite of this example may be replaced by a bisulfite or thefree sulfurous acid, as it has been specified in Letters Patent No. 613,578.

What I claim is 1. An improvement in the manufacture of blue dyestuffs, consisting. in treating a sulfonic gallocyanin derived from a nitrosoal kylbenzylanilinsulfonic acid, by sulfurous acid.

2. An improvement in the manufacture of blue dyestuffs, consisting in treating a sulfonic gallocyanin derived from the nitrosoethylbenzylanilinsulfonic acid by sulfurous acid.

3. As a new article of manufacture, the herein-described blue dyestuff obtained from a gallocyanin derived from a nitrosoalkylbenzylanilinsulfonic acid, the said dyestuff being soluble in sodium acetate with a paleblue coloration and giving with concentrated sulfuric acid a reddish solution turning to blue by addition of an oxidizing agent, this dyestuff dyeing chromium-mordanted fibers in blue shades.

In witness whereof I have hereunto signed my name, this 13th day of February, 1902, in the presence of two subscribing witnesses.

CHARLES DE LA I-IARPE.

Witnesses GEO. Grrrom), AMAND BITTER. 

